I watched the video for cleaning your filter by taking the top off and inserting the water hose, etc. It said to make sure your filter plumbing is disconnected from your pool. I left my pool open all year and everything is still connected (and I've never disconnected anything). How can I do this deep cleaning without pushing the gunk back into my pool? Could I just put the multi port valve on the "closed" setting? Or do I have to actually disconnect the pipes from the filter?